Developing lifesaving medicines and medical procedures depends on clinical trials to determine how well the new drug or procedure works in humans. But a report released April 1 finds major flaws in the way these studies are conducted by leaving out key segments of the population.

The EDICT—Eliminating Disparities in Clinical Trials—study found that older people, women, minorities, disabled people and residents of rural areas were excluded or underrepresented in the vast majority of tests.

Less than 1 percent of the U.S. population takes part in clinical trials. The researchers, based at the Baylor College of Medicine in Houston, say that although 61 percent of all cancer cases occur in older Americans, only 25 percent of those taking part in national clinical trials were over age 65. Older people are also routinely left out of clinical trials of illnesses associated with aging, such as Alzheimer’s disease, arthritis and incontinence.

They’re not the only ones who get the cold shoulder. “We found that children and adolescents are underrepresented as well,” says EDICT lead researcher Armin D. Weinberg of Baylor.

So are minority ethnic groups. Among those who participated in clinical trials to test new cancer drugs between 1995 and 1999, African Americans, Asian-Pacific Islanders, Hispanics and Native Americans collectively accounted for less than 10 percent of the total. The problem of underrepresentation becomes even more striking in light of recent advances in understanding how genetic factors in different groups can influence the response to treatment. Researchers now recognize that people respond differently to medications based in part on their genetic makeup.

The reasons for such low participation vary. On the one hand, the EDICT study found that doctors often don’t recommend that patients participate because they aren’t aware of the studies, mistrust the researchers, fear losing control of the patient’s care or believe it will increase paperwork and record keeping. On the other hand, patients are put off by lengthy and complex consent forms, vague information about insurance coverage of clinical trials and doubts about safety .

The report called for several changes to get more people from underrepresented groups into trials, beginning with steps individuals themselves can take.

Patients diagnosed with, say, diabetes might go on a weight loss and exercise program. “But you might also ask your doctor, ‘Is there something besides the routine approach that might be worth looking into? Is there a study I could participate in?’ ” Weinberg says.

The report also pushes for regulatory changes and incentives for the pharmaceutical industry that would assure broader participation in clinical trials, and it suggests that medical journal reports analyze how well a trial reflects the group affected by the disease under study. The researchers also encourage more public education for English- and non-English-speaking groups, more help to people in navigating the medical system and closing the gaps in insurance coverage for trial participants.

“This report presents a comprehensive solution to a serious issue,” says Beth A. Jones, a cancer epidemiologist at the Yale University School of Medicine who focuses on health disparities. “However, as suggested, we’re not going to convince people to participate unless we find a way to cover their out-of-pocket expenses, including transportation, child care, elder care and lost wages.”

The four-year project was conducted jointly by the Chronic Disease Prevention and Control Research Center and the Intercultural Cancer Council at Baylor. It was funded by an unrestricted grant from drugmaker Genentech Inc.